The present invention relates to equipment for the application of seal labels to containers. In particular, the present invention relates to labelling equipment suitable for use in affixing a revenue stamp to the topmost portion of a packet of cigarettes.
U.S. Pat. No. 4,718,216 discloses an item of equipment designed to operate in conjunction with a cigarette packaging machine utilizing two wrapping lines, in which the packets of cigarettes turned out by each line are formed progressively into a vertical stack by an elevator driven intermittently with a push-up type feed action and stationed next to a relative labelling device.
Each such device essentially comprises a suction roller by which the labels are conveyed singly and in succession, held tightly against the peripheral face, first toward a gumming device and then to a station at which each one is affixed to the bottom packet of the stack formed by the elevator.
The periphery of each suction roller is furnished with a plurality of fork elements capable of radial movement in relation to the roller and able also, by means of suction and employing the tips of the relative prongs, to restrain single labels on which a coating of adhesive material has been deposited. In the process of affixing a label to a packet at the bottom of the relative stack, the packets above are elevated from the object packet by a distance such as will allow one fork element of the roller to engage the top of the packet between its prongs. Consequently, before a successive packet can be brought into the area where the labels are affixed, each packet to receive a label in this manner must be lifted, together with the stacked packets above, by a distance significantly greater than the depth of the single packet as measured in the vertical stacking direction.
This substantial movement also occupies a somewhat lengthy interval of time, in order to safeguard the packets from mechanical stresses that could result in damage, and as a result, significant limitations are placed on the operating speed of the equipment in question, hence also of the packaging machine as a whole.
A further drawback of the equipment as disclosed in U.S. Pat. No. 4,718,21 derives from the fact that labels are folded over the tops of the packets in a position whereby a central portion of each label is applied to one vertically disposed end face of the packet and the two end flaps of the label are attached to the two opposite and larger horizontally disposed faces. In the course of the label being affixed to the packet, by reason of the considerable distance separating the uppermost face of the packet and the bottom face of the packet immediately above, which has already received a relative label, it happens on occasion that a bottom flap of the label affixed previously can come adrift from the corresponding horizontal face of the packet immediately above and tend toward a position substantially perpendicular to this same face; in this event, when the bottom packet is lifted subsequently as already intimated, the loose part of the label in question can become creased in an irregular fashion, and even crumple up completely.
The object of the present invention is to provide equipment of the type in question, such as will be devoid of the drawbacks briefly described above and reflecting the prior art.